Accession Number:

ADA270799

Title:

Degradation of Three Related Bis(Pyridinium) Aldoximes in Aqueous Solutions at High Concentrations: Examples of Unexpectedly Rapid Amide Group Hydrolysis

Descriptive Note:

Corporate Author:

ARMY MEDICAL RESEARCH INST OF CHEMICAL DEFENSE ABERDEEN PROVING GROUND MD

Personal Author(s):

Report Date:

1993-08-01

Pagination or Media Count:

7.0

Abstract:

The principal initial degradation products of two bispyridinium aldoxime organophosphate-inhibited acetylcholinesterase reactivators, 1 HI-6 and 3 HS-6, in concentrated nonbuffered aqueous solutions approximating potential therapeutic dosage concentrations were found to be the carboxylic acid derivatives 2 and 4 formed from the hydrolysis of the amide functional group. Compounds 2 and 4 were prepared by heating 1 and 3 in the presence of high concentrations of hydroxylamine hydrochloride and characterized by 1H and 13 C NMR, IR, and UV analyses. Estimates of the rates of hydrolysis of the amide groups in 1 and 3 and in model compounds 5, 7, and 8 under similar conditions were determined. The unexpectedly rapid hydrolysis of the amide groups in 1 and 3 was attributed to both the hydrogen ion catalysis of the concentrated aqueous solutions of the unusually acidic bispyridiniumaldoximes 1 and 3 and general acid catalysis by the aldoxime group.

Subject Categories:

  • Organic Chemistry
  • Physical Chemistry
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE